Section 9 Chapter 52 - Regular Expressions

Question 1

|

Answer 1

OR

Question 2

?

Answer 2

Optional (preceding element)

Question 3

*

Answer 3

zero or more (preceding element)

Question 4

+

Answer 4

one or more (preceding element)

Question 5

Regular Expression

Answer 5

A simple way to describe a set

Question 6

Regular expression for a 0 followed by any binary string

Answer 6

0(0|1)+

Question 7

Common uses of regular expressions (3)

Answer 7

• To match patterns to text files
• By compilers to recognise syntax
• By programs to validate input

Question 8

Regular language

Answer 8

A language that can be represented with a regular expression (or a FSM)

Question 9

Relationship between regular expressions and FSM

Answer 9

They are equivalent ways of describing a regular language